1. Field of Invention
The present invention relates to a liquid-crystal device and electronic equipment incorporating the liquid-crystal device. More particularly, the present invention relates to a liquid-crystal device which prevents scanning electrodes from shorting with each other when the electrodes are produced by partly arranging a narrow portion in the electrode width of an electrode strip serving as a scanning electrode or a data electrode.
2. Description of Related Art
Conventionally, a liquid-crystal device that employs a TFD (Thin Film Diode) device, for example, includes a transparent substrate, namely a so-called array substrate, on which a TFD device and a pixel electrode are formed, and an opposing substrate opposing the transparent substrate.
Polarizers are respectively glued onto the surfaces of the transparent substrate and the opposing substrate, the surfaces being opposite to the opposing surfaces. Alignment layers are formed on the opposing surfaces of the transparent substrate and the opposing substrate. A liquid crystal layer and spacers are arranged between these opposing alignment layers.
FIG. 17 is a plan view showing a major portion of the opposing substrate of the above-referenced liquid-crystal device, and FIG. 18 is a cross-sectional view of the major portion of the opposing substrate, taken along line XVIII-XVIIIxe2x80x2 in FIG. 17. These figures are intended to explain the construction of the opposing substrate, and dimensions, sizes, and thicknesses of components shown here are different from the dimensional relationship of the actual opposing substrate.
Referring to FIG. 17 and FIG. 18, a plurality of color material layers 21 are formed on the opposing substrate 20, and a matrix of a light-shielding layer 22, constructed of chromium or the like, is arranged between the color material layers 21.
Further arranged on the opposing substrate 20 is a protective layer 23 which covers the color material layers 21 and the light-shielding layer 22, as shown in FIG. 17 and FIG. 18. The color material layers 21, the light-shielding layer 22 and the protective layer 23 form a so-called color filter. Referring to FIG. 18, the protective layer 23 has a step portion 23b formed by the color material layer 21 on the outermost outline of an effective region and a light-shielding layer outline portion 22a that forms the outermost configuration of the light-shielding layer 22. The protective layer 23 also has a step portion 23c formed by the thickness of the protective layer 23 at a protective layer peripheral portion 23a external to the light-shielding layer outline portion 22a. The total thickness of the step portion 23b and the step portion 23c, i.e., the height from the top surface (an unformed region 26 of the protective layer) of the opposing substrate 20 to the top surface of the protective layer 23 in the effective region 27, is approximately 5 xcexcm in the typical liquid-crystal devices.
The protective layer 23 has a plurality of elongated rectangular electrode strips 24 formed thereon which function as scanning electrodes or data electrodes.
The electrode strips 24 are formed of a transparent conductive film such as an ITO (Indium Tin Oxide) film, and are formed on the protective layer 23 (a formation region 25 of the protective layer) as shown in FIG. 17 and FIG. 18, extending over to the unformed region 26 of the protective layer 23 beyond the protective layer peripheral portion 23a. 
The unformed region 26 of the protective layer represents an area where no protective layer 23 is formed, and specifically indicates a region surrounding the protective layer 23, where the top surface of the opposing substrate 20 is exposed.
The electrode width of the electrode strip 24 in typically available high-definition liquid-crystal devices is 100 xcexcm or so, and the spacing between the electrode strips 24 (hereinafter referred to as a wiring gap G) is typically equal to or narrower than 20 xcexcm. Particularly, high-definition liquid-crystal devices have a wiring gap G of 12 xcexcm or smaller.
The elongated rectangular electrode strips 24, constructed of ITO, are manufactured through a so-called photolithographic process. Specifically, the electrode strips are produced through the following manufacturing steps, including the formation of an ITO layer on the protective layer 23 and the opposing substrate 20 through sputtering or the like, the formation of a positive resist layer on the ITO layer, the patterning of the positive resist through exposure and development, and the etching of the ITO using the patterned resist as a mask.
Since the wiring gap G is extremely narrow, compared to the electrode width of the electrode strip 24, and is subject to variations, the wiring gap G is visually checked using a microscope or the like after the formation of the electrode strips 24.
Since the variations in the wiring gap G become a cause of the position shift of the electrode strips 24 relative to a pixel electrode arranged on the transparent substrate, it is considered the most preferable to inspect the wiring gap G in the formation region 25 of the protective layer 23.
Since a high-reflectance light-shielding layer 22 is present beneath the transparent electrode strip 24 in the formation region 25 of the protective layer 23, particularly in the effective region 27, light rays reflected from the light-shielding layer 22 make it difficult to visually recognize the electrode strip 24 and inspect the wiring gap G in the formation region 25 of the protective layer 23. The inspection of the wiring gap G is normally performed outside the effective region 27, based on the fact that the electrode strips 24 have a constant electrode width in the longitudinal direction thereof.
In the formation step of the above-referenced electrode strips 24, the thickness of a positive resist stacked onto the ITO layer becomes occasionally thicker than a rated thickness in the area of the step portions 23b and 23c. Exposure tends to be insufficient in an area where the thickness of the positive resist is thicker than the rated value, and part of the positive resist is left in the area of the step portions 23b and 23c after development. As shown in FIG. 17, the presence of a resist residue is a cause of the generation of a burr 24x of the electrode strip 24 and the generation of a bridge 24y that causes a shorting between adjacent electrode strips 24, thereby becoming a remote cause of a drop in the yield of the liquid-crystal device.
The generation of the burr 24x and the bridge 24y makes the electrode width of the electrode strips 24 inconstant in the longitudinal direction thereof, the inspection of the wiring gap G outside the effective region 27 becomes meaningless, and an increase in the yield of the liquid-crystal device is difficult.
Short-circuiting between adjacent electrode strips 24 frequently occurs in a high-definition liquid-crystal device having a smaller wiring gap, thereby lowering the yield of the high-definition liquid-crystal device.
The present invention has been developed in view of at least the above problem, and it is an object of the present invention to provide a liquid-crystal device which at least is free from short-circuiting between adjacent electrodes, presents a high yield in manufacturing process, and facilitates the measurement of a wiring gap.
A liquid-crystal device of one exemplary embodiment of the present invention includes a plurality of color material layers arranged on a substrate, a light-shielding layer surrounding each color material layer, a protective layer covering the color material layers and the light-shielding layer, and a plurality of electrode strips arranged on the protective layer and extending from a formation region of the protective layer to an unformed region of the protective layer. The electrode width of the electrode strip on a step portion in the protective layer may be set to be narrower than the electrode width of the electrode strip in the protective layer in an effective region of the liquid-crystal device.
In the liquid-crystal device, the electrode width of the electrode strip may be narrowed in the area where the protective layer has the step portion thereof, and with this arrangement, the spacing between the electrode strips (hereinafter referred to as a wiring gap) in the step portion of the protective layer is widened, and short-circuiting between the electrode strips in the step portion may thereby be prevented.
In another exemplary embodiment of the present invention, in the liquid crystal device described above, part of the electrode width of the electrode strip within the unformed region of the protective layer may be set to be equal to the electrode width of the electrode strip on the protective layer in the effective region.
In the liquid-crystal device, the electrode width of the electrode strip may be narrower at the step portion of the protective layer and the electrode width of the electrode strip in the unformed region of the protective layer may be set to be equal to the electrode width of the electrode strip on the protective layer in the effective region. With this arrangement, the wiring gap of the electrode strips arranged on the step portion of the protective layer increases, and short-circuiting between the electrode strips in the step portion may thus be prevented.
Since the electrode width in the unformed region of the protective layer is equal to the electrode width in the effective region, the wiring gap is measured in the unformed region of the protective layer, and the measurement of the wiring gap may not be hindered by light reflected from the light-shielding layer.
In another exemplary embodiment of the present invention, in the liquid crystal device as described above, a pair of sides of the electrode strip forming the outline of the electrode strip in the longitudinal direction thereof in the unformed region of the protective layer lie in the extensions of a pair of sides of the electrode strip forming the outline of the electrode strip in the longitudinal direction thereof in the protective layer in the effective region.
Since in the liquid-crystal device, the pair of sides of the electrode strip that form the outline of the electrode strip in the longitudinal direction thereof in the unformed region of the protective layer lie in the extensions of the pair of sides of the electrode strip that form the outline of the electrode strip in the longitudinal direction thereof, in the protective layer in the effective region, the wiring gap may be precisely measured in the unformed region of the protective layer.